Intravenous magnesium sulfate rapidly alleviates headaches of various types

Abstract

Background. - Circumstantial evidence points to the possible role of magnesium deficiency in the pathogenesis of headaches and has raised questions about the clinical utility of magnesium as a therapeutic regimen in some headaches. Methods. - We evaluated the efficacy of intravenous infusion of 1 gram of magnesium sulfate (MgSO 4) for the treatment of patients with headaches and attempted to correlate clinical responses to the basal serum ionized magnesium (IMg 2+) level. We also determined if patients with certain headache types exhibit low serum IMg 2+ as opposed to total serum magnesium. Using a case-control comparison at an outpatient headache clinic, a consecutive sample of patients presenting with a moderate or severe headache of any type were included in the study. Of the 40 patients in the study (mean age 33.2 ± 9.4 years; range 14 to 55; 11 men [39.2 ± 7.3 years] and 29 women [37.8 ± 10.2 years]), 16 patients had migraines without aura, 9 patients had cluster headaches, 4 patients had chronic tension-type headaches, and 11 had chronic migrainous headaches. Total serum magnesium was measured with atomic absorption spectroscopy and a Kodak Ektachem DT-60. Sensitive ion selective electrodes were utilized to measure serum IMg 2+ and ionized calcium (ICa 2+); ICa 2+/IMg 2+ ratios were calculated. Results. - Complete elimination of pain was observed in 80% of the patients within 15 minutes of infusion of MgSO 4. No recurrence or worsening of pain was observed within 24 hours in 56% of the patients. Patients treated with MgSO 4 observed complete elimination of migraine-associated symptoms such as photophobia and phonophobia as well as nausea. Correlation was noted between immediate and 24-hour responses with the serum IMg 2+ levels. Immediate pain relief was observed in 32 (80%) of 40 patients (P<0.001). In 18 of the 32 patients, pain relief persisted for at least 24 hours (P<0.005). Of these 18 patients, 16 (89%) had a low serum IMg 2+ level. Total magnesium levels in contrast in all subjects were within normal range (0.70-0.99 mmol/L). No side effects were observed, except for a brief flushed feeling. Of the 8 patients with no relief, only 37.5% had a low IMg 2+ level. Patients demonstrating no return of headache or associated symptoms within 24 hours of intravenous MgSO 4 exhibited the lowest initial basal levels of IMg 2+. Non-responders exhibited significantly elevated total magnesium levels compared to responders. Although most subcategories of headache types investigated (ie, migraine, cluster, chronic migrainous) exhibited low serum IMg 2+ during headache and prior to intravenous MgSO 4, the patients with cluster headaches exhibited the lowest basal levels of IMg 2+ (P<0.01). All headache subjects except for the chronic tension group exhibited rather high serum ICa 2+/IMg 2+ ratios (P<0.01, compared to controls). Conclusions. - Intravenous infusion of 1 gram of MgSO 4, results in rapid relief of headache pain in patients with low serum IMg 2+ levels. Measurement of serum IMg 2+ levels may have a practical application in many types of headache patients. Low serum end brain tissue ionized magnesium levels may precipitate headache symptoms in susceptible patients.